This is clutch question #2...
I have a 1973 340 cast crank and externally balanced. I have a Mcleod clutch out of another car that is virtually brand new and it has been balanced. I am unsure whether it was balanced on its own or as an assembly with a flywheel.
I am thinking of having it balanced to the flywheel on my 340 so I can use it.
Any issues doing this in general? Should I balance the flywheel and clutch on an externally balanced engine?
Thanks

As far as I know, the disc and pressure plates have always been nuetral balanced so really not nec. to bother.

Correct answer. Pressure plates are supposed to be neutral balanced out of the box.

Everyone will now chime in with their horror story.

Think about it...Literally millions of replacement clutches have been installed over the years without balancing by the installer.

I'd assemble the crank, flywheel, harmonic damper, bobweights. Get it balanced. Then add the pressure plate and see if the balance changes.

If the pressure plate is so far out that it affects balance, when you balance the assembly with the pressure plate installed, the next time you change your clutch the engine will need to be rebalanced.

R.

In every case I've seen, if the clutch was balanced with the engine there will be some sort of witness mark on the pressure plate flange so it can be reassembled in the same position.

Let me clarify a bit. I bought a slightly used complete clutch set up at a swap meet. It has never been on the engine I have. That said, if they come from the manufacturer balanced mine shouldn't have any weight welded to the pressure plate housing unless it was balanced with another flywheel, correct? maybe I can just cut the weight that was welded onto the pressure plate housing off and run it?

If there's a weight welded on it it's most likely been put there by the manufacturer to neutral balance it. Does it look like it was welded on by someone else? i.e. non painted welds or rust around the weld. The flywheel is balanced specific to your engine not the pressure plate.

It is not a pretty weld but the paint is identical to the paint on the rest of the housing. The previous owner said he sent it back to Mcleod to be "refurbished" but he didn't mention balancing (and to be honest I didn't really notice the weld on the housing when I bought it anyway). There is also some writing in sharpie (2,700#@.300) which I confirmed with a Mcleod service tech that was something they would write on a refurbished or otherwise tested unit. He said it had something to do with the clamping force and so on. What he couldn't tell me is whether or not the pressure plate housing was balanced by itself or with a flywheel. He did say that they do weld weight to the housings and that some of them aren't the prettiest welds you have ever seen.
I kind of want to run it but I may just hold onto it for a future project and deal with it then.
It is a 10.9" set up and I am wondering if that is a little much for this car anyway...

You are overthinking this.

The pressure plate is balanced at the factory, like I said in my first post. Think about it, there's not a lot of material to remove to balance, so instead they weld a weight where it needs to go.

It's that simple.

Yes, with the pressure plate disk pushed back 0.300" the force it exerts is 2700 lb. So it will require a clutch leg that's stronger than a stock clutch would.

Years ago my brother and I succumbed to the "more's better" theory and bought and installed a 3400 lb pressure plate. It was not fun to drive in town, and I now know that the engine that was in front of it didn't need it either. I think we wore the fingers off it when the throwout bearing seized. Kids!

R.

I get what you're saying, and you're right, I am probably overthinking it(I tend to do that).

Just to clarify , the disc never gets balanced except by the manufacture. It is balanced to neutral .I'm not a small block guy but I thought the 340 was a internally balanced engine. I know the 360 was externally balanced. Are you sure what engine you have?

73 340 was an externally balanced cast crank motor

I keep going back to the fact that there is a weight that was welded to the pressure plate housing for some reason by someone else and I don't know why which is my bad for buying it that way without asking.
I think I'll cut to the chase and take the flywheel and pressure plate to a machine shop and have them checked. I just don't wan't to put the thing in the car and have an issue I could have fixed now.
I'll let you know if I wasted my money...

internal balance engine. flywheel is neutral balanced, so if one flywheel is replaced with another, you need to replace with a neutral balance flywheel. the pressure plate is also neutral balanced. any pressure plate that is neutral balanced can be used with any flywheel that is neutral balanced. mix and match any neutral balanced components with each other and no problems will arise on an internal balanced engine. simple as that. pressure plates are neutral balanced with weights welded to them. flywheels that are neutral balanced have holes drilled to balance.

NO, it would have been balanced by the clutch maker, I have seen weights welded to pressure plate covers in the past.

it would be very hard to balance the clutch disc as it wears and is rarely in the same place twice ... clutch disc is moot, the only thing you need to worry about is the pressure plate.

I'm not sure how you would go about confirming neutral balance on the pressure plate, you could attempt to have it balanced with your flywheel but I'm not sure how that is done with a flywheel that is not neutral balance?

I am not sure either...At this point I just want to be sure that the pressure plate housing is actually neutral balanced.

I haven't looked at it in sometime but I am 99.9999999% sure my McLeod PP has extra weights welded on it for neutral balance , as is a Centerforce I have.

Since PP patterns are pretty much standard, unless it's a Ford LONG type PP you shouldn't have any problem just bolting that PP to a neutral balance flywheel and have it checked.

Talk to your guy that is doing the balancing , they should be able to check it out pretty easily.

Now that I think about it they should be able to spin your flywheel , which would be a good idea to do and confirm the amount of imbalance and correct it if the flywheel has been resurfaced at all, then put on the PP and make sure that the imbalance hasn't changed ?

Is the PP cover , including the weights/welds, all painted over or does it look like some scraped the paint off to add the weights ?

He's already answered your last question, there is factory paint over the welded on weight. It's a factory applied weight to balance the pressure plate. He refuses to listen to reason and insists on spending good money to find out that I'm right.

At this point I throw up my hands and say whatever.

R.

This is wrong. I have an arbor and I balance EVERY disc. Most discs are off 8-10 grams.

Most shops don't do the disc and it really can be picking the pepper out of the fly poop.


To the OP...is this a Borg & Beck or Borg & Beck/Long cover?

If so. I have a hard time believing McLeod didn't replace the cover. Those covers are heat treated and if you weld on them it will FAIL, and you can bank on that.

Welding a washer on the PP is a piss poor way to balance it. You can drill the spring stands or use press in weights and get it close and then take the rest out of the FW.

It is a balanced ASSEMBLY.

If they welded on th cover it is most likely NOT neutral balance, and it probably shouldn't be. See my other post.

BTW, McLeod doesn't own that color of red.

I've been running stick shift cars for 50 years and have seen many pressure plate covers with welded on weights from different manufactures. Over those years I have also had a number of engine rotating assemblies balanced. Some wanted the pressure plate to be included , most not. Never, not one asked for a disc.